function memoObj() {
	this.x = [];
	this.y = [];
	this.alpha = [];
	this.a = [];
	this.R = [];
	this.spd = [];

	this.para = [];
	this.beta = [];
}
memoObj.prototype.num = 3;

memoObj.prototype.init = function(i) {
	//for (var i = 0; i < this.num; i++) {
		this.x[i] = can.width + Math.random()*800;
		this.y[i] = Math.random() * can.height * 0.5+ can.height * 0.1;
		this.a[i] = Math.round( Math.random()*20)* Math.PI/24; //用来控制透明度
		var r = 3;
		this.R[i] = r + 2 * Math.sin(this.a[i]); //正弦函数控制半径的变化

		this.para[i] = Math.random()*0.2 + 0.2;
		this.beta[i] = 0;

		this.spd[i] = Math.random()*1+1;
	//}
}

memoObj.prototype.draw = function() {
	var r = 3;

	ctx.save();
	ctx.shadowBlur = 10;
	ctx.shadowColor = "#ffffff";

	for (var i = 0; i < this.num; i++) {
		this.a[i] += time* Math.PI / 10000; //控制透明度
		this.alpha[i] = Math.sin(this.a[i]);
		this.R[i] = r + 2 * Math.sin(this.a[i]); //正弦函数控制半径的变化
		if (this.a[i] >= Math.PI) { //a不要大于2π
			this.a[i] = 0;
		}

		if (this.x[i] > 0 && this.x[i] < can.width) {
			ctx.beginPath();
			ctx.arc(this.x[i], this.y[i], this.R[i], 0, Math.PI * 2);
			ctx.fillStyle = "rgba(255,255,255," + this.alpha[i] + ")";
			ctx.fill();

			this.beta[i] += time*Math.PI/10000;
			this.y[i] += Math.sin(this.beta[i]) * this.para[i];
		}

		

		this.x[i] -= time * (ane.spd / 2 + this.spd[i]) / 20; //向左前进

		if (this.x[i] < -10 && dark.a1 > 20 && dark.a2 > 100) {
			this.init(i);
		}

	}
		ctx.restore();
}